A combination clothes washer-dryer appliance is especially suitable for installation and use in tightly confined living spaces such as those in motor homes, yachts, recreation vehicles, and condominiums. Combination washer-dryer appliances are available with either a non-vented condenser dryer or a vented dryer.
A combination washer-non-vented condenser dryer has a closed outer tub constructed with a sealed separate condenser section to enable a drying process. A wash load of clothes is contained in an inner tub or basket that is mounted for rotation inside the outer tub. An air-circulating fan draws air internally from the rear of the outer tub, passes the air over a heating element of a heater box assembly attached to the top of the outer tub, and returns the heated air to the front of the outer tub by way of an inlet through a door seal. Warm air travels through and collects moisture from a wash load tumbling in the basket as it rotates. The hot, moist air extracted from the wash load travels through the condenser section where a cold water stream, at a typical rate of 2 gal/hour (7.57 l/hr), condenses the moisture into water. The water is then pumped out of the appliance through its water discharge hose. Relatively dry air is then drawn back over the heating element to repeat the process. The air-circulating fan, a one shot cut-out or thermal fuse cable, and a thermistor located in the heater box assembly control the air temperature.
A combination washer-vented dryer performs a drying process by means of a water-sealed outer tub, with an exhaust outlet located above a washing high water operating level and at the rear of the outer tub. Outside air enters beneath a blower assembly and is passed over a heating element encased in a cast aluminum heater housing attached to the top of the outer tub. Forced air developed by the blower assembly enters the front of the outer tub through an inlet opening in a door seal. Air circulates through a wash load tumbling in the basket as it rotates inside the outer tub. Moisture-carrying air extracted from the wash load exits the outer tub through an exhaust outlet pipe.
Clothes dryer appliances sold in the United States must meet the UL 2158 Dryer Fire Containment Standard, which entails passing four fire containment tests including static tumbler (drum load fire), dynamic tumbler (drum load fire), static tumbler (base lint fire), and dynamic tumbler (base lint fire) tests. Meeting this UL standard is particularly challenging for vented dryer appliances because they do not operate with a closed air system.
What is needed, therefore, is a fire containment system for vented clothes dryer appliances. What is especially needed is a fire containment system that can be implemented in a commercially available combination clothes washer-vented dryer appliance with minimal structural changes to it.